1. Field of the Invention
This invention relates generally to the recording and reproducing or other transmission of information signals, such as, video signals, and more particularly is directed to the processing of such signals so as to eliminate or at least reduce the distortion thereof that may result from the angular modulation of at least a portion or component of the signals and then the filtering of the angularly modulated component or signals for the recording thereof.
2. Description of the Prior Art
It is well known that, in recording video signals, it is advantageous to record at least a portion of the video signals as a frequency modulation on a carrier having a relatively high frequency. More particularly, when recording color video signals which include a luminance component and a chrominance component, it is known to separate such components and then to frequency modulate the luminance component on the carrier having a relatively high frequency, while the chrominance component is frequency converted so as to have its frequency band shifted below the frequency band of the frequency modulated luminance component which passes through a suitable high pass filter, whereupon the filtered frequency modulated luminance component and the frequency converted chrominance component are combined to provide composite video signals which may be recorded in successive parallel tracks on a magnetic tape. Moreover, in the recording operation of existing apparatus for recording and reproducing video signals, at least a high frequency portion of the video signals, that is, the luminance component, is pre-emphasized in a pre-emphasis circuit prior to the frequency modulation thereof, and, in the reproducing or playback operation of such apparatus, the reproduced frequency modulated luminance component is demodulated and then de-emphasized in a de-emphasis circuit which has a characteristic complementary to that of the pre-emphasis circuit for reducing the so-called FM noise signal from the demodulated luminance component. However, in such existing apparatus, the high pass band filter acts to depress the amplitude of the frequency modulated component of the recorded video signals at the portion thereof which had been subjected to the greatest pre-emphasis and, upon reproduction, the amplitude variation of the frequency modulated component will be accentuated. When the frequency modulated component of the reproduced signal is demodulated, a distortion will appear at the pre-emphasized portion and, after de-emphasis of the demodulated luminance component, so-called "smear noise" will appear in the resulting reproduced video signals.